Fuel control apparatus

ABSTRACT

An apparatus for controlling a fuel injection system for an engine includes a cam rotatable in response to engine temperature and a cam follower selectively engageable with different portions of the cam. The output of the cam follower provides one input of an arrangement for varying the position of a control stop on a metering pump for the system, and the said selective engagement is operated during engine starting to provide an increased fuel supply.

United States Patent Hughes et al. Oct. 24, 1972 541 FUEL CONTROL APPARATUS [56] References Cited [72] Inventors: Ronald William Hughes, Bir- UNITED STATES PATENTS j j g 2,865,356 12/1958 Groezinger ..123/140 MC o a 2,984,232 5/1961 Amdt et al ..123/179 L [73] Assignee: Joseph Lucas (Industries) Limited,

Bimingham, England FOREIGN PATENTS OR APPLICATIONS [22] Filed: Dec. 23, 1970 882,298 11/1961 Great Britain ..123/139 AM [2]] Appl. No.: 100,860 Primary Examiner-Laurence M. Goodridge Att0rneyl-lolman & Stern [30] Foreign Application Priority Data [57] ABSTRACT An apparatus for controlling a fuel injection system 1970 Great Bntam "560/70 for an engine includes a-carn rotatable in response to engine temperature and a cam follower selectively en- [52] US. Cl ..123/1790G, 123/139 AM, gageable with different portions of the cam The 123/14 123/1791 put of the cam follower provides one input of an ar- [51] Int Cl F02 17/00 rangement for varying the position of a control stop on a metering p p for the y andthe Said selec [58] Field of Search ..123/139,139 AM,'140, five engagement is Operated during engine Starting to 123/140 MC, 179 A, 179 L provide an increased fuel supply.

10 Claims, 3 Drawing Figures PATENTED BT m2 3.699 '.941

- SHEET 2 0F 2 INVENTOR ATTORNEYS FUEL CONTROL APPARATUS This invention relates to an apparatus which controls a fuel injection system for an engine by varying the position of a control stop on a metering pump for the said system.

According to the invention, an apparatus of the foregoing kind comprises a first cam means for moving the first cam in response to'the temperature of the engine, a first cam follower co-acting with the first cam, means actuated during engine starting for varying the response of the first cam follower to movement of the first cam, a second cam movable by the first cam follower, a second cam follower engaged with the second cam and movable relative thereto in response to an engine operating condition and means for transmitting the resultant position of the second cam follower to the control stop.

An embodiment of the invention will now be described by way of example and with reference to the accompanyingdrawings in which:

FIG. 1 shows, somewhat diagrammatically, a section through a control apparatus,

FIG. 2 is a section on lines 2-2 in FIG. 1, and,

FIG. 3 is a view on arrow 3 in FIG. 2.

The apparatus has a body which includes a chamber 11 through which passes, in use, a coolant for an associated engine. Within chamber 11 is a capsule 12 having a stud l3 axially movable in response to changes in temperature of capsule 12 and threadedly engaging a plunger 14. Plunger 14 is biased towards capsule 12 by a spring 17. Plunger 14 is slidable within a further plunger 15 which is in turn slidable in body 10. A pin 45 extends through plunger 14 into a pair of slots 46 in plunger 15. A spring 16 urges plungers 14, 15 apart so that pin 45 engages one end of slots 46.

The end 18 of plunger 15 is formed as a valve control member and combines with a port 19 in the body 10 to provide a metering orifice through which, an additional air supply may reach the engine.

An edge cam 20 is rotatably mounted in the body 10 and includes an arm 21 which engages a slot 22 in plunger 15. A cam follower 23 is supported on a spindle 24 mounted in body 10. Cam follower 23 includes follower members 25, 26 engageable with different portions of edge cam 20 and also includes a portion 27 engageable by the plunger of a solenoid 28. Also supported on spindle 24 is a crank 29 which engages a cam plate 30 pivotally mounted in body 10. A torsion spring 44 engages body 10 and cam follower 23 to bias the latter in a clockwise direction, as seen in FIG. 1, and a spring 31 biases cam plate 30 in an anticlockwise direction, as seen in FIG. 3, into engagement with a crank 29. Cam follower 23 thus controls the angular position of cam plate 30.

A diaphragm assembly 32 includes a diaphragm 33 sealingly engaged between a part of the body 10 and a cover member 34. The diaphragm assembly also includes a number of reinforcing members 35 with which is engaged an eye bolt 36. Pivoted on the bolt 36 is a cam follower 37 in the form of a pair of arms 38 supporting between them a roller 39 which engages the cam plate 30. A pair of inwardly directed abutments 40 on the arms 38 engage the cam plate 30 to steady the cam follower 37.

The roller 39 abuts one end of a piston-like member 41 which is slidable in the casing 10 and whose other end abuts a control stop forming part of a known type of fuel injection pump 43. The member 41 is biased towards the cam plate 30 by the pressure of fuel within the pump 43.

In use a rise in the temperature of the engine coolant in the chamber 11 causes the stud 13 to move the plunger 14, against the bias'of spring 17 and, since spring 16 is sufficiently strong to overcome frictional forces in the apparatus, also moves plunger 15, so as to rotate the cam 20 in an anticlockwise direction as shown in FIG. 1. Follower member 25 is in engagement with cam 20, under the influence of spring 44, and cam follower 23 rotates clockwise, also as shown in FIG. 1. The corresponding movement of crank 29 and cam plate 30 moves member 41 to the right, as shown in FIG. 3, resulting in a reduction of the stroke of the metering pump 43. The side of the diaphragm assembly 32 remote from the cam plate 30 is subjected to the pressure at the inlet manifold of the engine. Decreasing pressure in the manifold causes the cam follower 37 to move upwards as shown in FIG. 2, also resulting in a reduction in the stroke of the metering pump 43. The solenoid 28 is energized to extend the plunger thereof only during engine starting. At all other times fuel supply to the engine is responsive to manifold depression and to a function of coolant temperature dependent on the profile of the cam 20 engaged by the follower member 25. During starting, however, the cam 20 is engaged by'the follower member 26 resulting in an increased fuel supply which is a different function of coolant temperature.

During cold starting an additional air supply is available to the engine via the port 19. As engine temperature rises this air supply is reduced by downward movement of plunger 15, as seen in FIG. 1. When port 19 is fully closed continued movement of stud 13 and plunger 14 is accommodated by spring 16, slots 46 being sufficiently long to prevent this movement from causing damage to the apparatus.

Having thus described our invention what we claim as new and desire to secure by Letters patent is:

1. An apparatus for controlling a fuel injection system for an engine by varying the position of a control stop on a metering pump in said system comprises a first cam, means for moving the first cam in response to the temperature of the engine, a first cam follower ineluding first and second cam follower elements selectively engageable with the first cam, means actuated during engine starting for moving said first cam follower to engage one of said elements with the first cam and dis-engage the other of said elements to vary the response of the first cam follower to movement of the first cam, a second cam movable by the first cam follower, a second cam follower engaged with the second cam and movable relative thereto in response to an engine operating condition and means for transmitting the resultant position of the second cam follower to the control stop.

2. An apparatus as claimed in claim 1 in which the means for moving the first cam comprises a temperature sensitive capsule mounted in a chamber through which, in use, passes a coolant for the engine.

3. An apparatus as claimed in claim 2 in which the means for moving the first cam includes a plunger arrangement engaged with the capsule and with the first cam.

4. An apparatus as claimed in claim 3 in which the plunger arrangement provides a control member for a metering orifice through which, in use, air can flow to the engine.

5. An apparatus as claimed in claim 4 in which the plunger arrangement includes means for permitting relative movement between the control member and the remainder of the plunger arrangement when said metering orifice is fully closed.

6. An apparatus as claimed in claim 1 in which said means actuated during engine starting comprises an electro-magnetic actuator.

7. An apparatus as claimed in claim 1 in which movement of the first cam follower is transmitted to the second cam by means of a crank rotatable by the first 

1. An apparatus for controlling a fuel injection system for an engine by varying the position of a control stop on a metering pump in said system comprises a first cam, means for moving the first cam in response to the temperature of the engine, a first cam follower including first and second cam follower elements selectively engageable with the first cam, means actuated during engine starting for moving said first cam follower to engage one of said elements with the first cam and dis-engage the other of said elements to vary the response of the first cam follower to movement of the first cam, a second cam movable by the first cam follower, a second cam follower engaged with the second cam and movable relative thereto in response to an engine operating condition and means for transmitting the resultant position of the second cam follower to the control stop.
 2. An apparatus as claimed in claim 1 in which the means for moving the first cam comprises a temperature sensitive capsule mounted in a chamber through which, in use, passes a coolant for the engine.
 3. An apparatus as claimed in claim 2 in which the means for moving the first cam includes a plunger arrangement engaged with the capsule and with the first cam.
 4. An apparatus as claimed in claim 3 in which the plunger arrangement provides a control member for a metering orifice through which, in use, air can flow to the engine.
 5. An apparatus as claimed in claim 4 in which the plunger arrangement includes means for permitting relative movement between the control member and the remainder of the plunger arrangement when said metering orifice is fully closed.
 6. An apparatus as claimed in claim 1 in which said means actuated during engine starting comprises an electro-magnetic actuator.
 7. An apparatus as claimed in claim 1 in which movement of the first cam follower is transmitted to the second cam by means of a crank rotatable by the first cam follower.
 8. An apparatus as claimed in claim 1 which includes means for biasing the second cam against movement imparted thereto by the first cam followers.
 9. An apparatus as claimed in claim 1 in which the second cam follower is movable relative to the second cam in response to the pressure in the engine inlet manifold.
 10. An apparatus as claimed in claim 1 in which the means for transmitting the position of the second cam follower to the control stop comprises a piston member engaging both the second cam follower and the control stop. 